1. Field of the Invention
The field of the invention relates to software protection technologies.
2. Description of the Prior Art
Computing security has increased in importance as security threats have become ubiquitous. In particular, software protection has gained importance as software piracy has become commonplace.
Often times, software applications are encrypted in order to prevent unauthorized use. Under authorized circumstances, the software is decrypted prior to run-time, much like a data file would typically be decrypted. However, once a software application is decrypted, the application resides in memory in an unencrypted and vulnerable state.
One prior art solution that seeks to avoid this problem is to decrypt at run-time the program instructions that constitute a software application. Specifically, encrypted program instructions are fetched from memory by a microprocessor for execution by the microprocessor. A decryption module within the microprocessor decrypts the program instructions. The decrypted program instructions are then passed to other elements of the microprocessor for execution. Problematically, this prior art approach limits the microprocessor to executing encrypted software applications.